Electronic – How to decrease nrf24l01 transceiver range


I've just got my Nrf24l01 but then I found out that the working signal range for the module is 100m and above. Our real intention for the module is to let the nrf24l01(Receiver) out of range for about 5m in order to activate the alarm.

The purpose of our project is for anti-theft alarm which sounds the alarm if the module is out of range. We only need a short distance in order for the alarm to work since our research project is only for personal use.

We have an idea which we want to clarify if it is possible, it works by having the (receiver) to reach a fixed distance value in the coding of the arduino and when the (receiver) goes beyond that value, it will activate the alarm or beep. We want to ask if our idea is possible and if yes, can you help us how to code the arduino?.

I don't have any background in making a code for arduino but I know how to program an arduino using a ready-made code from the internet.

Best Answer

No, not a fixed distance, but you can certainly reduced the expectable range, simply by reducing the output power of the transmitter, or by decreasing the sensitivity of the receiver.

These systems have no way of knowing distance – they can just "hear" or "hear not" the transmitter. How "loud" a transmitter is at the receiver depends on how loud it transmitted, or what happened to the signal from the transmitter to the receiver.

So, you need to tone down what the receiver can sense.

This can be either done by configuring the involved chips to use less power to transmit, or by using worse antennas, for example.

You'll find out that it's extremely difficult to achieve a reliable range by adjusting power – effects of random orientation, obstacles (e.g. humans) between transmitter and receiver and so on are much much larger than a few meters of difference in distance.

So, you might find out that it's conceptually impossible to define an "alert" radius without accepting a high number of false alarms or being too late to alarm.

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